/* 
 * Copyright 2001-2009 Terracotta, Inc. 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 
 * use this file except in compliance with the License. You may obtain a copy 
 * of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 *   
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 
 * License for the specific language governing permissions and limitations 
 * under the License.
 * 
 */

package org.go.scheduler.database.delegate;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.go.spi.ClassLoadHelper;
import org.slf4j.Logger;

/**
 * <p>
 * This is a driver delegate for the PostgreSQL JDBC driver.
 * </p>
 * 
 * @author <a href="mailto:jeff@binaryfeed.org">Jeffrey Wescott</a>
 */
public class PostgreSQLDelegate extends StdJDBCDelegate {
	/**
	 * <p>
	 * Create new PostgreSQLDelegate instance.
	 * </p>
	 * 
	 * @param log
	 *          the logger to use during execution
	 * @param tablePrefix
	 *          the prefix of all table names
	 */
	public PostgreSQLDelegate(Logger log, String tablePrefix, String schedName, String instanceId, ClassLoadHelper classLoadHelper) {
		super(log, tablePrefix, schedName, instanceId, classLoadHelper);
	}

	/**
	 * <p>
	 * Create new PostgreSQLDelegate instance.
	 * </p>
	 * 
	 * @param log
	 *          the logger to use during execution
	 * @param tablePrefix
	 *          the prefix of all table names
	 * @param useProperties
	 *          use java.util.Properties for storage
	 */
	public PostgreSQLDelegate(Logger log, String tablePrefix, String schedName, String instanceId, ClassLoadHelper classLoadHelper, Boolean useProperties) {
		super(log, tablePrefix, schedName, instanceId, classLoadHelper, useProperties);
	}

	//---------------------------------------------------------------------------
	// protected methods that can be overridden by subclasses
	//---------------------------------------------------------------------------

	@Override
	protected Object getJobDataFromBlob(ResultSet rs, String colName) throws ClassNotFoundException, IOException, SQLException {
		if (canUseProperties()) {
			InputStream binaryInput = null;
			byte[] bytes = rs.getBytes(colName);
			if (bytes == null || bytes.length == 0) {
				return null;
			}
			binaryInput = new ByteArrayInputStream(bytes);
			return binaryInput;
		}
		return getObjectFromBlob(rs, colName);
	}

	/**
	 * <p>
	 * This method should be overridden by any delegate subclasses that need
	 * special handling for BLOBs. The default implementation uses standard
	 * JDBC <code>java.sql.Blob</code> operations.
	 * </p>
	 * 
	 * @param rs
	 *          the result set, already queued to the correct row
	 * @param colName
	 *          the column name for the BLOB
	 * @return the deserialized Object from the ResultSet BLOB
	 * @throws ClassNotFoundException
	 *           if a class found during deserialization cannot be found
	 * @throws IOException
	 *           if deserialization causes an error
	 */
	@Override
	protected Object getObjectFromBlob(ResultSet rs, String colName) throws ClassNotFoundException, IOException, SQLException {
		InputStream binaryInput = null;
		byte[] bytes = rs.getBytes(colName);

		Object obj = null;

		if (bytes != null && bytes.length != 0) {
			binaryInput = new ByteArrayInputStream(bytes);

			ObjectInputStream in = new ObjectInputStream(binaryInput);
			try {
				obj = in.readObject();
			} finally {
				in.close();
			}

		}

		return obj;
	}
}

// EOF
